Package and laminate thereof



P 26, 1967 D. w. SEIDLER 3,343,663

PACKAGE AND LAMINATE THEREOF Filed Oct. 24, 1965 I NVEN TOR. Don H.Sla/r' fiGENT United States Patent 3,343,663 PACKAGE AND LAMINATETHEREGF Don W. Seidler, Rocky River, Ohio, assignor to The Dow ChemicalCompany, Midland, Mich a corporation of Delaware Filed Oct. 24, 1965,Ser. No. 504,964 Claims. (Cl. 206-46) ABSTRACT OF THE DISCLOSURE Alaminate packaging film is composed of a layer of flexible printablematerial, a polyethylene layer, a biaxially oriented polypropylenelayer, a polyethylene layer, a metal foil layer and a polyethylenelayer, the layers are adhered together and the composite film isparticularly suited for packaging granular hygroscopic materials such assugar.

This invention relates to an improved package and a laminate forformation of such package. It more particularly relates to a compositelaminate suitable for the preparation of a flexible package and apackage formed therefrom.

The packaging of granular hygroscopic material in flexible packages hasoftentimes proven unsatisfactory because of inadequate protection forthe contents of such a package. Granular materials have a tendencyduring shipping and storage to perforate or puncture the flexiblepackage, and permit moisture vapor to enter the space within thepackage. Such moisture vapor leads to the liquification of the contents,spoilage thereof and the leakage of the contents onto adjacent packages,frequently rendering them unsatisfactory for sale. oftentimes softdrinks containing sugar granules, instant coffee and like materialsrequire protection from moisture vapor and protection from visiblelight. Desirably, a package has an external printable surface.

It is an object of this invention to provide an improved package ofhygroscopic granular materials.

It is a further object of this invention to provide an improved packageof soft drink concentrate containing granular sugar.

A further object of this invention is to provide a flexible packagingfilm which provides durability and high strength resistance to puncture,has a printable surface and a heat scalable surface, is a moisture vaporbarrier and a barrier to visible light.

These benefits and other advantages in accordance with the presentinvention are achieved in a composite packaging film comprising afirst'layer of a flexible material adapted to receive printing,a'first'layer of polyethylene adhered to the flexible, printable layer,a layer of biaxially oriented polypropylene adhered to the firstpolyethylene layer, a second layer of polyethylene adhered to thepolypropylene layer, a layer of metallic foil adhered to the secondpolyethylene layer, and a third layer of polyethylene adhered to themetallic foil.

Also contemplated within the scope of the present invention is a packagecomprising an envelope having at least a first panel and a second panelhermetically sealed together about the periphery and defining a spacetherebetween, a hygroscopic granular material disposed within the space,each of the panels comprising an outer layer of a flexible printedmaterial, a first layer of polyethylene adhered to the outer layer, alayer of biaxially oriented polypropylene adhered to the first layer ofpolyethylene, a second layer of polyethylene adhered to the layer ofbiaxially oriented polypropylene, and a layer of a metallic foil adheredto the second layer of polyethylene and a third or inner layer ofpolyethylene adhered to the layer of aluminum foil.

Further features and advantages of the present invention become moreapparent from the following specification when taken in connection withthe drawing wherein:

FIGURE 1 is a schematic representation of a multilayer compositepackaging film in accordance with the invention.

FIGURE 2 is a partly-in-section view of a package in accordance with theinvention.

In FIGURE 1 there is illustrated the composite packaging film inaccordance with the present invention, generally described by thereference numeral 10. The packaging film 10 comprises a flexible,printable layer 11 having adhered to one major face thereof a firstpolyethylene layer 12. A biaxially oriented polypropylene layer 13 isadhered to the first polyethylene layer 12 remote from the cellulosiclayer 11. A second polyethylene layer 14 is adhered to the polypropylenelayer 13 and is remotely disposed from the first polyethylene layer 12.A metal foil layer 15 is adhered to the second polyethylene layer 14remote from the polyethylene layer v13. A third polyethylene layer orinner surface 16 is adhered to the foil layer 15.

Beneficially, in preparing laminates in accordance with the presentinvention, the outer flexible layer or printable layer 1'1 may beprepared from regenerated cellulose, paper, cellulose acetate, polyesterfilm (polyethyleneterephthalate) or like readily printable material.

Advantageously, the biaxially oriented polypropylene layer is combinedwith the cellulosic layer by extrusion lamination employing polyethyleneas a hot melt adhe sive. In such a process, the first polyethylene layeris extruded into a converging nip formed between adjacent nip rolls ofwhich the layer 11 and the biaxially oriented polypropylene 13 pass. Thepolyethylene in a molten condition is extruded into the nip and thelayers 11 and 13 are firmly bonded together by means of the extruded hotmelt layer 12. The third polyethylene layer 16 is applied to thealuminum or metallic foil by hot melt extrusion or hot lamination toform a composite of foil and polyethylene equal to the layers 15 and 16.Extrusion lamination employing polyethylene as a hot melt adhesiveprovides a satisfactory means of joining the polyethylene metal foil tothe composite of layers 11, 12 and 13.

If desired, laminates, in accordance with the present invention, may beprepared by contacting a polyethylene layer onto the printable layer andsubsequently laminating the biaxially oriented polypropylene layerthereto, a metal foil such as the layer '15 may be coated with thepolyethylene on both sides and subsequently heat laminated to thebiaxially oriented polypropylene-containing composite. The sequence oflamination is not critical and may be accomplished in any of theconventional manners. However, it is critical that at no time during theformation of the laminate that the temperature is sufliciently high tocause significant shrinkage or deorientation of the polypropylene layer.

In FIGURE 2 there is illustrated schematically a partly cutaway view ofthe package in accordance with the present invention generallydesignated by the reference numeral 20. The package 20 comprises a firstpanel 21 and a second panel 22 in generally continuing side-by-siderelation wherein the outer surface of each of the panels 21 and 22 isthe printable layer and the inner surface is the polyethylene layer. Agranular hygroscopic material 23 is contained within the package. Thepanels 21 and 22 are secured to each other by means of peripheral heatseals 25, 26, 27 and 28 wherein the polyethylene layers 16 are securedto each other. The panels 21 and 22 define an internal space 29.

In order to prepare satisfactory flexible packages in accordance withthe present invention, the first polyethylene layer desirably has athickness from about 0.40 to about 1.5 mils, the polypropylene layer hasa thickness of from about0.50 to about 2 mils, the second polyethylenelayer has a thickness of about 0.40 to about 1.5 mils, the metallic foilhas a thickness of about 0.30 to about 1 mil and beneficially is analuminum foil, the third polyethylene layer has a thickness of fromabout 0.70 to about 3 mils, and the printable substrate advantageouslyhas a thickness from about 0.25 to about 6 mils. The thicknesses dependprimarily uponthe characteristics desired in the resultant package.

The printable layer beneficially is regenerated cellulose such ascellophane or paper which may vary from 12 pound to 100 pound paper, theWeight referring to the weight of 500 sheets measuring 24 inches by 36inches.

Generally thinner laminates, in accordance with the present invention,are employed for relatively small packages, whereas the heavierlaminates usually are more desirable for large packages. F or example, alaminate wherein the cellulosic layer is 25 pound paper, the firstpolyethylene layer has a thickness of 0.40 mil, the biaxially orientedpolypropylene layer has a thickness of 0.50 mil, the second polyethylenelayer has a thickness of 0.40 mil, and 0.35 mil aluminum foil employedwith a third polyethylene layer having a thickness of 1.0 mil iseminently suitable for packages containing a granular hygroscopicmaterial such as soft drink mixes having granular sugar therein, inquantities up to about 4 ounces. A thicker laminate such as a laminatewherein the first layer of polyethylene hasa thickness of about 1.5mils, the biaxially oriented polypropylene layer has a thickness of 2mils, the second polyethylene layer has a thickness of 1.5 mils, a 1 milaluminum foil layer, and a 3 mil polyethylene layer and 100 pound paperis eminently suited for packaging granular calcium chloride in packagescontaining as much as 25 pounds. Laminate packages containinghygroscopic granules in accordance with the invention are remarkablyresistant to breakage and abrasion and resist exceptionally wellshipping and storage.

As is apparent from the foregoing specification, the present inventionis susceptible of being embodied with various alterations andmodifications which may differ particularly from those that have beendescribed in the preceding specification and description. For thisreason, it is to be fully understood that all of the foregoing isintended to be merely illustrative and is not to be construed orinterpreted as being restrictive or otherwise limiting of the presentinvention excepting as it is set forth and defined in the heretoappended claims.

What is claimed is:

1. A composite packaging film comprising a first layer of a flexiblematerial adapted to receive printing, a first layer of polyethyleneadhered to the flexible, printable layer, a layer of biaxially orientedpolypropylene adhered to the first polyethylene layer, a second layer ofpolyethylene adhered to the polypropylene layer, a layer of metallicfoil adhered to the second polyethylene layer,

and a third layer of polyethylene adhered to the metallic foil, thelayers of the laminate being adhered together with a strength equivalentto that obtained by extrusion lamination.

2. The film of claim 1, wherein the printable layer is regeneratedcellulose, paper, cellulose acetate or ,polyethyleneterephthalate.

3. The film of claim 1, wherein the first and second polyethylene layershave a thickness of from about 0.4 to about 1.5 mils.

4. The film of claim 1, wherein the polypropylene layer has a thicknessof from about 0.5 to about 2 mils and the third polyethylene layer has athickness of from about 0.5 to about 3 mils.

5. The film of claim 1, wherein the first layer has a thickness of fromabout 0.25 to about 5 mils.

6. A package comprising an envelope having at least a first panel and asecond panel hermetically sealed together about the periphery anddefining a space therebetween, a hydroscopic granular material disposedwithin the space, each of the panels comprising an outer layer of aflexible printed material, a first layer of polyethylene adhered to theouter layer, a layer of biaxially oriented polypropylene adhered to thefirst layer of polyethylene, a second layer of polyethylene adhered tothe layer of biaxially oriented polypropylene, a layer of metallic foiladhered to the second layer of polyethylene and a third, or inner layer,of polyethylene adhered to the layer of aluminum foil.

7. The package of claim 6, containing granular sugar.

8. The package of claim 6, wherein the outer layer is printedregenerated cellulose, paper, cellulose acetate orpolyethyleneterephthalate having a thickness of from about 0.25 to about6 mils, the first polyethylene layer has a thickness of from about 0.4to about 1.5 mils, the polypropylene layer has a thickness of from about0.5 to about 2 mils, the second polyethylene layer has a thickness offrom about 0.4 to about 1.5 mils, the metallic foil has a thickness ofabout 0.3 to about 1 mil, the third polyethylene layer has a thicknessof from about 0.7 to about 3 mils.

9. The package of claim 6, wherein the metallic foil is aluminum foil.

10. The package of claim 6, wherein the printed layer is regeneratedcellulose.

References Cited UNITED STATES PATENTS 2,679,969 6/ 1954 Kichter 229-353,136,468 6/:1964 Keller 22.9- 3.5 3,221,873 12/ 1965 Bowes 206-6533,246,061 4/1966 Blatz 1161-402 3,274,004 '9/1966- Curler.

LOUIS G. MANCENE, Primary Examiner.

1. A COMPOSITE PACKAGING FILM COMPRISING A FIRST LAYER OF A FLEXIBLEMATERIAL ADAPTED TO RECEIVE PRINTING, A FIRST LAYER OF POLYETHYLENEADHERED TO THE FLEXIBLE, PRINTABLE LAYER, A LAYER OF BIAXIALLY ORIENTEDPOLYPROPLYENE ADHERED TO THE FIRST POLYETHYLENE LAYER, A SECOND LAYER OFPOLYETHYLENE ADHERED TO THE POLYPROPYLEN LAYER, A LAYER OF METALLIC FOILADHERED TO THE SECOND POLYETHYLENE LAYER, AND A THIRD LAYER OFPOLYETHYLENE ADHERED TO THE METALLIC FOIL, THE LAYERS OF THE LAMINATEBEIN ADHERED TOGETHER WITH A STRENGTH EQUIVALENT TO THAT OBTAINED BYEXTRUSION LAMINATION.